Equivalent transmission-line model for vias connected to striplines in multilayer print circuit boards

Abstract

Vias are typical discontinuities for high-speed signal transmission in printed circuit boards. Previous work has studied the through-hole via connections from the top layer to the bottom between microstrip traces and proposed an equivalent transmission-line model for impedance matching between traces and vias. In this paper, the equivalent transmission-line model is extended for the via structures connected to striplines based on modal decomposition. Both single-ended and differential cases are discussed, and the effects of the model parameters on the performance of signal transition are also investigated. The extended equivalent transmission-line model is accurate and fast to be embedded in circuit simulators for via and link-path analysis. Further, it could provide straightforward criteria to design and optimize via structures for better signal integrity.